The sunk cost fallacy
You've spent years preparing, collecting, learning, building, and developing. It would be a shame to stop now. Sure, it might make you miserable the rest of your life, but you've invested so much into this already. If you quit, then whatever has happened in the past is now all for nothing.
Except it's not. What you have done up to this point has made you who you are today.
Sometimes it’s worth taking the loss and moving on. It’s especially worth it if it’s holding you back from doing something better.